The steel shot column does not have the compression abilities of a lead column. If you go too tight if can cause the wad ti distort and rip apart upon exiting tbe muzzle causing your shot column to open up immediately and get worse. I used to shoot an improved modified choke in my browning. The key to keeping a tight waterfowl pattern with steel is keeping the wad and shot column as one for as long as possible. The real key to shooting waterfowl is actually leading the head and not the body. They are optical illusions per se because their heads bareky show up in your vision and your body will naturally go to the largest object form which is the body. You have to be extra vigilant to get on the head and lock into one bird. I always liked the pull through method on swingin birds.
Leading the head, I agree with. It's tough to do, but it yields the best results. And like you, I also prefer the pull-through method on birds.
I don't agree with the shot column stuff, though. I don't agree that the key is keeping the shot with the wad as long as possible. In fact, I don't want a long string of shot at all. I want a ball of shot, which is accomplished by stripping the wad from the shot as soon as possible. This is how the Kick's and Patternmaster choke tubes function. Patternmasters utilize studs inside the choke to grab the wad, whereas the Kick's chokes utilize reverse-porting to grab the wad. If you have a long shot string, you're not going to hit the bird with very many pellets... you only hit them with part of the string. However, when you send a massive ball of shot at them, you hit them with many more pellets at the same time, thereby resulting in a more lethal impact, and far fewer cripples.
Here's is what I meant by the "choke too tight - no such thing" comment... It was more of a joke really, but I still stand by it... Yes, you can overchoke a gun so much that the pattern blows apart. It's especially easy to do using steel shot. My comment was pointed at the patterns themselves, not so much the choke. IMO, there's no such thing as a pattern that's too tight for waterfowling. Waterfowl are tough birds with thick feathers... The more pellets on put in them the better. Non-toxic loads are expensive enough as it is. The last thing I want to do is burn them up on cripples that are trying to swim away. More pellets on impact = lesser chance of a cripple. I want pellets in the head, pellets in the bill, and broken wings. Yes, with a tighter pattern your chances of missing the bird go up. But it teaches you to be a better wingshooter, IMO. And for me, I'd much rather miss clean than be sailing crippled birds all day long. When you get dialed in with a super tight pattern, you rarely miss and the birds you shoot are dead... I mean fuggin stonecold, crumpled, doing a backflip over the decoys type of dead.
